Resonance-type oscillators generate an oscillating signal having a frequency based on the natural resonance frequency of the resonator. Additionally, such oscillators may include a current source (an amplifier core, for example) to supply constant energy to the resonant circuit and replenish its intrinsic losses. Generally, to have a low-power mode of operation, the core is sized to have the maximum transconductance (gm) for a given bias current. However, if the negative resistance of the core is not sufficient (e.g., internal losses of the resonant circuit are greater than the negative resistance), the oscillations may be damped. In such a case, the core's current may be increased until the negative resistance is sufficient, and the core may be resized to have the maximum gm for the new current. In many cases, this can result in greater power consumption by the oscillator circuit, based on the resized core and/or increased current.
Additionally, the load capacitance seen by the resonator may be reduced to the minimum value possible for the best negative resistance available for a desired frequency range. In an extreme example, the load capacitance may be reduced to zero, maximizing the gain of the oscillator circuit. However, reducing the load capacitance of the oscillator circuit can come at the expense of a large frequency shift due to an incorrect load capacitance seen by the resonator.